Sealed electrical connector



May Z1, 1968 E. J. SCHAEFER ET A1. 3,384,860

SEALED ELECTRI CAL CONNECTOR Filed Oct. 20, 1965 5 Sheets-Sheet l I l l l JV @a 70 Jr-ma Invent@ 715: au mi c/zefef mldlllezer er; 3y MLM, vm@

May 2, 1968 E. .1. scHAEr-ER ET AL 3,384,8@0

SEALED ELECTRICAL CONNECTR 3 Sheets-Sheet 2 Filed Oct. 20, 1965 5 SheetsnSheet 5 E J SCHAEFER ET AL SEALED ELECTR ICAL CONNECTOR Filed Oct. 20, 1965 United States Patent O 3,384,860 SEALED ELECTRICAL CONNECTQR Edward J. Schaefer and Donald L. Ellenberger, Bluffton, Ind., assignors to Franklin Electric Co., Inc., Bluffton, Ind., a corporation of Indiana Filed Uct. 20, 1965, Ser. No. 498,805 3 Claims. (Cl. 339-94) ABSTRACT OF THE DISCLOSURE This disclosure deals with an electrical connector designed for use while submersed in a high pressure liquid. The connector includes a resilient insulating member made of an incompressable material, which is placed under initial compression by the parts. A portion of the member is left exposed to the high pressure liquid, and the member is shaped such that pressure of the liquid increases the effectiveness of the seal.

It is an object of the present invention to provide an electrical connector for use while submersed in a fluid capable of causing a short circuit if the fluid reached the electrical conductor parts of the connector.

It is another object of the invention to provide an electrical connector of the foregoing character, which is especially suited for use with a submersible motor assembly.

Still another object of the invention is to provide an electrical connector of the foregoing character, which may be used under very high fluid pressure conditions.

Still a further object of the invention is to provide a sealed electrical connector of the foregoing character, wherein the effect of high fluid pressures acting on the connector is to increase the effectiveness of the seal.

A still further object is to provide a sealed electrical connect-or of the foregoing character, wherein an insulator par-t of the electrical connector, which cooperates with the other parts to form a seal, may be very easily replaced when necessary.

Still another object is to provide an electrical connector of the foregoing character, which may be used under extreme temperature conditions.

vOther objects and advantages of the invention will become Iapparent from the following description taken in conjunction with the accompanying figures of the drawings, in which:

FIG. 1 is a fragmentary elevational view, on a reduced scale, of a submersible motor assembly including sealed electrical connectors embodying the invention;

FIG. 2 is a sectional view taken on the line 2-2 of FIG. 1;

FIG. 3 is an enlarged sectional view of a portion of the assembly shown in FIG. l, showing the electrical connector;

FIG. 4 is a view similar to FIG. 3 but showing the parts in partially assembled relation;

FIG. 5 is an enlarged end view taken on the line 5-5 of FIG. 7, and showing another form of the electrical connector;

FIG. 6 is a sectional view taken on the line 6-6 of FIG. 5;

FIG. 7 is an enlarged sectional view similar to FIG. 6 of parts of the apparatus prior to assembly; and

FIGS. 8 to 12 are enlarged views of parts of the electrical connector.

Generally, an electrical connector embodying the invention is adapted for use with first and second units while submersed in a high pressure fluid. The electrical connector comprises a first electrical connector part fastened to the first unit and a second electrical connector "ice part fastened to the second unit. The two units are releasably secured together when in use, and the first and second electrical connector parts include mating conductor portions which are embraced by a sealing plug forming a seal and thereby preventing the high pressure fluid from gaining access to said portions. The sealing plug is pressed bythe two units tightly against the portions, and at least one unit is constructed such that a portion of the sealing plug is exposed to the high pressure fluid when the units are secured together. The construction of the connector is such that the pressure of the fluid acting on the sealing plug tends to increase the effectiveness of the seal around the conductor portions of the connector.

Further, the sealing plug may be readily removed from the other parts of the electrical connector and replaced by la different sealing plug when necessary.

In greater detail, FIG. l illustrates a submersible motor assembly which may include electrical connectors ernbodying the invention. The assembly shown in FIG. 1 cornprises la plurality of motor units or modules 20, 21 and 22 which are connected together by intermediate units 23 in vertically stacked end-to-end relation for operation in unison. At the lower end of the assembly a lower end termination unit or module 24 is connected by an intermediate unit 23 to the motor module 22. The module 24 may, for example, form a seal at the lower end of the assembly and complete the electrical circuit of the motor modules. At the upper end of the assembly is provided an auxiliary unit or module 25 which is secured *to the upper end of the uppermost mot-or module 20. The auxiliary module 25 may include, for example, pressure equalizing apparatus for the assembly, a vertically extending shaft 25 which has its lower end connected to the rotor lshaft '32 of the motor module 20 and its upper end adapted to be connected to a device to be driven, rotary shaft seals for preventing an ambient fluid from entering the interior of the module 25 around the shaft 25 and thrust bearings for supporting the thrust of the device -being driven.

lPower for energizing the motor modules 20, 21 and 22 is obtained from an electric power supply (not shown), the power supply being connected to the motor modules by means of an electric cable 26. In the construction shown, the motor modules 20, 21 and 22 are three phase motors, and consequently the cable 26 includes three wires 39, 40 and 41 (FIG. 2).

With reference to lFIGS. l and 2, at its lower end the auxiliary module 25 includes a radially outwardly extending flange 27 having longitudinally extending holes formed therethrough which receive 'bolts 28 to secure the flange 27 to the upper end of the module 20. Just above the flange 27, the auxiliary module 25 comprises a generally tubular portion 29 having a hollow bore 31 (FIG. 2). Within the lbore 31 are positioned the upper end of a motor shaft 32 of the motor module 20 and the lower end of the shaft 25' of the auxiliary module 25. A sleeve type splined coupling 33 is also provided to connect the two shafts 25 and 32 together.

The motor module 2d, which may be identical with the modules 21 and 22, comprises a stator 43 (FIGS. 3 and 4) including a stator winding (not shown) which is enclosed within a sealed housing formed by a cylindrical outer shell 44, a cylindrical inner liner 46, and upper and lower end rings 47 and 45 (FIGS. 3 and 6). The shell 4 and the liner 45 are secured as by welding to the outer and inner peripheries, respectively, of the end rings. Further, the space around the stator windings is filled with a potting compound 48 which serves to transfer heat from the stator windings to the surrounding members.

In addition to the holes for the bolts 28, the flange 27 has formed therethrough three longitudinally extending holes 36, 37 and 38 which receive parts of the electrical connectors for connecting the wires 39, 40 and 41 to the windings of the motor module 20. Longitudinally extending holes are also formed through the end ring 47 for parts of the electrical connector, one such hole 51 for the electrical connector associated with the wire 40 being shown in FIGS. 3 and 4.

Each electrical connector comprises a longitudinally extending generally cylindrical metal prong 52 which is centrally located with the cylindrical opening 51 of the end ring 47 of the motor module. The lower end 53 of the prong 52 is electrically connected to the windings of the stator of the motor module 20 and is embedded in the potting compound 48. The prong S2 is held spaced from the end ring 47 by a cup shaped insulating member 56 which is positioned within the hole 51 of the end ring 47. The lower portion of the hole 51 is recessed or counterbored as at 57, and the insulator member 56 is received within the recessed portion 57. The upper end 58 of the insulator member 56 engages a shoulder formed at the upper end of the recess 57, such engagement preventing the insulator member 56 from being pulled upwardly out of the hole 51.

The prong 52 extends through a hole S4 formed in the bottom wall of the member 56, and when the motor module 20 is disconnected from the auxiliary module 25 (FIG. 4) the upper end portion of the prong 52 is exposed.

The wire 40 is covered by insulation 62 which is stripped back in successive layers to bare the end portion of the wire 40. The wire 40 is positioned coaxially within a tubular housing or sheath 66, and a generally cylindrical socket member 67 (FIGS. 3, 4, ll and 12) is secured to the lower end portion of the wire 49. An axial bore 68 is formed in the upper end of the socket member 67 and the end portion of the wire 40 is positioned Within the bore 68 and rigidly secured thereto. The socket member 67 extends from within the sheath 66 downwardly below the lower end of the sheath 66. The Wire 40 and the socket member 67 are spaced from the Walls of the tubular sheath 66, and the intervening space is filled with a potting and insulating compound 69. The socket member 67 may also be coated with a layer 70 of an insulating material such as Natvar.

At its lower end, the socket member 67 is provided with an axially extending bore 71 which is adapted to receive the upper portion of the prong 52. A spring clip 72 is mounted on the socket member 67, the spring clip 72 extending into the bore 71 as shown in FIG. l2 and ensuring a firm electrical connection between the prong 52 and the socket member 67 when the prong 52 is inserted into the bore 71. The construction of the spring clip is shown in FIGS. 1l and 12 and also in U.S. Patent No. 2,958,842.

The electrical Connector further includes a tubular seal or plug member 76 (FIGS. 3, 4 and 8) which is generally cylindrical and has an axially extending bore 77. The diameter of one end portion 78 of the bore 77 is enlarged, while the diameter of the other end portion is reduced. The body of the plug member 76 includes two portions 81 and 82 which are tapered on their outer peripheries. The portion 81 is at the end of the plug member 76 which includes the enlarged portion 78 of the bore 77, and from this end, the outer periphery of the portion 81 tapers radially outwardly and toward the other end of the plug member. The other portion 82 extends from the termination of the portion 81 to the opposite end of the plug member 76, and it tapers radially inward and away from the portion 81. The length of the portion 82 is substantially equal to the distance from the outer surface of the end ring 47 to the bottom of the cup shaped member 56. At the juncture of the two portions 81 and 82, the outer diameter of the portion 81 is greater than the outer diameter of the portion 82 thereby forming a radially extending shoulder 83, and the outer corner of the plug member 76 at the end which is adjacent the reduced diameter portion 7 of the bore 77 is rounded somewhat as shown at 84.

The diameter of the bore portion 78 is normally slightlyv less than the outer diameter of the lower portion of and receives the housing or sheath 66, and the reduced diameter portion 79 is normally slightly less than the diameter of and receives the prong 52. The remainder of the bore 77 has an internal diameter which is slightly less than the diameter of and receives the socket member 67.

The electrical connector further includes a wedge shaped sleeve 86 and a jam nut 87 for compressing the member 76 and securing the two electrical conductor portions of the electrical connector together. The outer diameter of the sleeve 86 is slightly less than the inner diameter of the hole 37 formed in the ange 27, and the inner periphery of the sleeve 86 is tapered similarly to the taper of the portion 81 of the plug 76.

To compress the plug member 76 during assembly, the sleeve 86 is forced downwardly by means of the jam nut 87, and the socket member 67 is forced downwardly by a split snap ring 88. The outer surface of the jam nut 87 is threaded adjacent its lower end, as indicated at 89, and mating threads 91 are formed on the inner periphery of the opening 37 above the sleeve 86. The ring 88 is located around a reduced diameter section 93 of the sheath 66, the portion 93 having as its boundries two shoulders or humps 94 and 96. The ring 88 is also located within a groove 97 formed in the inner periphery of the jam nut 87, the axial length of the groove 97 being such that the ring 88 is free to radially expand therein. When the ring 88 is located in the groove 97, the radial depth of the groove is such that the inner diameter of the ring 88 is less than the outer diameter of both of the humps 94 and 96.

To assemble the electrical connector `after the motor module 20 has been secured to the auxiliary module 25 by the bolts 28, the split `ring 88 is slipped over the lower end of the socket member 6-7 and forced over the hump 96 Iand into the reduced diameter section 93 of the sheath l66. Thereafter, the jam nut 87, the inner diameter of which is slightly greater than the outer diameter of the raised portions or humps I94 and 96, `is also slipped over the lower end of the socket member 67 .and the lower end of the sheath 66. When the upper end of the jam nut '87 reaches the reduced diameter section I93, 4the snap ring 88 is forced into the bore 90 of the jam nut 87. With the snap ring 188 within the upper end of the bore 90, the jam nut 187 is moved upwardly relative to the shea-th 66, and the snap ring 88 engages the hump 94, and thereby held against continued `upward movement relative to the sheath 66. Further upward movement of the jam nut 87 relative to the sheath 88 causes the nut 87 to slide upwardly relative to the ring 88 until the groove 97 reaches a ring 88, after which the ring 88 snaps into the groove 97.

Subsequently, the sleeve 86 is slipped over the lower end of the socket member 67 and the lower end of the sheath 66, `and then the plug member 76 is slipped over the lower end of the socket member 67 and the lower end of the sheath 66. Due to the previously described dimensions of the bore portions of the member 76 relative to the outer dimensions of the socket member 66, the bore portion v78 must be stretched slightly to get it over the sheath 66, and the center section of the bore must be stretched slightly 4to get it over the socket member 67. The stretch fit normally holds the member 67 attached to the socket and sheath members. Further, the bore portion 79 is coaxial with the opening of the bore 71 of the socket member 67. With the ja-m nut 87, the sleeve 86 and the plug member 76 in place -around the sheath 66 and the socket member 67, the socket member 67 is inserted into the hole 37 in the ange 27 and is moved into mating engagement with the prong 52. The plug member 76 is thereby moved into the opening or hole 51 of the end ring 47 .and the prong 59 enters the 'bore portion 79 of the 4member 76 and the bore 71 of the socket member 67, and the spring 72 establishes a rm electrical connection between the prong 52 and the socket member 67.

The sleeve 86 is moved downwardly and engages the tapered portion 81 of the plug member 76 and then the jam nut 87 is lowered and rotated to engage the threads 89 and 91. The snap ring r88 engages 4the hump 96, and as the jam nut I87 is threaded into the hole 37, the snap ring 88 presses downwardly against the hump 96 and forces the socket member 67 and the plug member 76 downwardly, the socket member being forced over the prong 52. Continued turning movement of the jam nut 87 causes its lower end 101 to engage the upper surface of the sleeve 86 and forces the sleeve 86 downwardly.

When the plug member 76 is pushed all the way into the hole 51, the lower end of the plug member 76 engages the Ibottom wall of the insulator member 56, and the shoulder S3 of the plug member 76 engages the outer surface of the end ring 47. Further downw-ard movement of the sleeve 86 relative to the plug member 76 causes the tapered portion 81 of the plug member 76 to be tightly compressed between the sleeve y86 and the outer surface of the lower end of the sheath `66, and the tapered portion 82 to be tightly compressed between the outer surface of the socket member 67 and the inne-r walls of the hole 51 and the me-mber 56, the inner walls of the hole 51 and the member 56 thus forming a cavity which receives a portion of the plug member 76. Compression of the plug member 76 may cause a portion 102 of the plug member 76 to be extruded upwardly between the sleeve 186 and the outer surface of the sheath 66, and causes another portion 103 to be extruded radially outwardly into an annular opening 164 provided between the lower end of the sleeve 86 and the upper surface -of the end ring 47. Without the annular space 104 yand the opening for the portion 192 of the plug member, excessive stress might develop on the parts of the connector because the plug member 76 is preferably made of rubber, which is generally incompressible. To further prevent excessive stress on the parts vdue to over tightening of the jam nut l87, a shoulder 106 is formed on the outer periphery of the jam nut 87 which engages a ledge 10'8 `of the ange 27 when the parts are completely assembled. The interior of the assembly is preferably tilled lwith a cooling and lubricating fluid, and an O-ring seal 109 (FIGS. 3 and 4) is positioned within a groove 111 formed in the outer periphery of the tubular portion 29 of the module 25, to prevent leakage of the uid between the tubular -portion 29 of the mo-dule 25 and the end ring 47 of the mot-or module 20.

After the electrical connector has been assembled as described, the assembly may be lowered into a deep well containing a liquid, where the assembly is subjected to extremely high pressure, without danger that the liquid will reach the electrical connector parts which carry electricity. The portion 81 of the plug member 76 is firmly pressed against the outer periphery of the sheath `66 by the sleeve 86 and thus prevents leakage of fluid between the sheath 66 and lthe plug member 76. Further, the shoulder 83 Iof the plug member 76 is firmly pressed Iagainst the upper face of the end ring 47 and thus prevents leakage of duid between the plug member and the end ring. In addition, the portion 82 of the plug member 76 is in sealing engagement with the wall of the bore 51 and the inner walls of the insulator member 56. These walls Iare preferably provided with a slight taper which is the same as the taper of the portion 82, and downward pressure on the plug member 76 causes the portion 82 to be jammed or wedged against these walls.

When the high pressure liquid within the hole `37 acts against the sleeve 36 and the -portion 102 of the plug member 76, the pressure of the liquid tends to force them downwardly. lSuch a downward force increases the compressive load on the portion S1 of the plug member 76 Iand hence the effectiveness of the seal between the plug member 76 and the sheath 66 and between the plug member and the upper face of the end ring 47. Further, the slight taper of the portion 82 of the plug member 76 causes the portion 82 to be more tightly jammed against the walls of the hole 5-1 and the insulator 56.

Consequently, the -plug member 76 provides a seal at relatively low pressure due to the initial compression `by the ysleeve 186, and it also provides a seal at extremely high pressure because such high pressure increases the effectiveness of lthe seal. The plug member 76 has the additional advantages in that it serves as lan electrical insulator as well as a seal and the plug member 76 may be easily assembled with the other parts of the electrical connector or removed for replacement when necessary. It has been found that, after a material such as a rubber has been in use for a relatively long time it tends to lose yits pliability and hence its effectiveness as a seal. By this invention the plug member 76 may be easily removed and replaced with a new plug member if it becomes ineffective.

Instead of assembling the parts as described above, the plug member 76, the sleeve 86 and the nut 88 could be connected to the socket member 67 and the sheath 66 and to the module 25 before the module 25 is secured to the motor module 20 by the bolts 28.Then, the plug member 76 would be compressed as described above when the modules 20 and 25 were secured together by the bolts 28.

In the assembly shown in FIG. 1, the windings of adjacent motors are connected together, either in series or in parallel by the intermediate units 23, and at the lower end of the assembly the electrical circuit is terminated, as by a wire connection in the lower end termination module 24. Electrical connectors constructed in accordance with this invention may also be provided to effect the foregoing electrical connections.

With reference to FIGS. 1, 5 4and 6, the two motor modules 20 and 21 are preferably identical and are connected together by the intermediate unit 23. The motor module 2@ includes the shell 44, the liner 46, the lower end ring 45 and a rotor shaft 128, and the motor module 21 includes an outer shell 44', .a liner 46', an upper end ring 47', and a rotor shaft 129. The intermediate unit 23 comprises a generally tubular member 117 having upper and lower radially extending flanges 118 and 119, respectively. Holes 120 are formed through the flanges 118 and 119, and bolts l121 extend through the holes and are threaded into holes formed in the end rings 4S and 47' to secure the member 117 to the motor :modules 20 and 21. Further, O-ring seals 122 are provided between adjacent surfaces of the member 117 .and the end rings 45 and 47 seal the connection between these members.

The member 117 includes an upward extension 123 and a downward extension 124 which project into the rotor cavities of the motor module 20' and 21, respectively, and support radial bearings 126 and 127, respectively. The rotor shafts 12'8 and 129 are positioned within the bearings 126 and 127, and the adjacent ends of the rotor shafts 12S and 129 are connected together by a splined coupling 131.

As previously stated, the motor modules and the intermediate units of the assembly form a sealed inner chamber which is prelled with a cooling and lubricating fluid, and uid passageways are provided for circulating the fluid. For example, axial bores 132 are formed in the rotor shafts 128 and 129, openings 133 are formed in the extensions 123 and 124 of the member 117, and radial holes 134 are formed through the coupling 131. A labyrinth seal 136 is preferably also provided between the inner periphery of the member 117 and the outer surface of the coupling 131 below the holes 134, the seal 136 serving to maintain the fluid within the two motor modules 20 and 21 substantially separated but allowing a 7 limited amount of fluid ow between the motors and 21 to equalize the pressure between them.

At the lower end of the motor module 20, the stator windings, indicated generally by the numeral 137, are connected to prongs 141, only one such prong being shown in FIG. 6. An opening or hole 142 is provided through the end ring 45 through which the prong 141 extends and a cup shaped insulator 143 is positioned around the prong 141 between the prong and the end ring 45. The prong 141 and the insulator member 143 are identical with the prong 52 and the insulator member 56 shown in FIG. 3.

The construction at the upper end of the motor module 21 is similar to that of the upper end of the :motor module 20. An opening 146 is formed in the end ring 47', which receives -a prong 147 and an insulating member 148 similar to those previously described. The prong 147 is electrically connected to the stator windings 149' of the motor module 21.

Four radially outwardly extending projections 150 are fromed on the member 117, and longitudinally extending bores are provided through three of the four projections 150, only one such projection 150 :and bore 151 being shown in FIG. 6. The bore 151 (FIG. 6) receives a double ended socket assembly 152 shown in detail in FIG. 9, and comprising an outer tube 153 having an outwardly extending shoulder or enlarged portion 154 formed thereon intermediate the ends thereof. Axially located within the tube 153 is a solid connecting rod 156 which has substantially the same length as the tube 153. At the ends of the connecting rod 156 are secured upper and lower sockets 157 and 158 having bores 159 and 161, lrespectively, formed therein at their inner ends, which receive the ends of the connecting rod 156. The connecting rod 156 is secured to the sockets 157 and 158, and the three members 156 to 158 are preferably coated with an insulating material such as Natvar, and the space between the member 156 to 158 and the tube 153 is lled with an insulating compound 162.

At their outer ends the sockets 157 and 158 have axial bores 163 and 164, respectively, formed therein, the portions of the sockets 157 and 158 having these bores extending outwardly beyond the ends of the tube 153, and the bores 163 and 164 being adapted to receive the prongs 141 and 147 respectively of the motor modules 20 and 21. Spring clips 165, similar to the clips 72, may be fastened to the sockets 157 and 158.

The socket assembly 152 shown in FIG. 9 is fastened to the intermediate unit 23 by inserting it into the bore 151 from the upper end thereof as seen in FIGS. 6 and 7. The :bore 151 is provided with a reduced diameter section 166 which forms a shoulder 167, and the increased diameter section 154 of the tube 152 is sized to engage the shoulder l167. The outer diameter of the portion 154 of the tube 153 is slightly less than the inner diameter of the main portion of the bore 151 so that the socket assembly 152 may be easily inserted into the bore 151 until the portion 154 engages the shoulder 167. 'I'he shoulder 167 is located such that the ends of the assembly 152 extend equal distances out of the ends of the bore 151, and consequently the portion 154 and the shoulder 167 properly locate the assembly 152 in the bore 151.

The yapparatus shown in FIGS. 6 and 7 further includes two plug members '167 and 168 which are identical with the plug member 76 shown in FIGS. 3 and `8. The radial dimensions of the assembly 152 relative to the plug members 167 and 168 are such that the plug members 167 and 168 must be stretched slightly in order to slip them over the ends of the assembly 152. Thereafter, the plug members 167 and 168 prevent the assembly 152 from falling out of the bore 151. The outer end portions of the bores 151 are tapered as at 165 and the tapered portion 170 of the plug members 167 and 168, which correspond to the portion 81 of the member 76, extend into the bore portions l165. The plug members 167 and 168 are also provided with shoulders 169 and 171 which are similar to the shoulder 83 of the plug member 76, and the shoulders 169 and 171 rest on the outer surfaces of the end rings 45 and 47 when the intermediate lunit; 23 is assen1- bled with the motor modules.

When assembling the intermediate unit 23 with the motor modules 20 and 21, the three socket assemblies 152 are rst positioned within the bores 151. of the member 117 from the upper end until the shoulders 167 are engaged by the enlarged portions 154 of the tubes 153. The plug members 167 and 168 are then slipped over the outer ends of the socket assemblies. Thereafter, the member 117 is preferably positioned under the lower end of the motor module 20, with the plug members 167 extending through the holes 142 and into the insulator members 143. As the bolts 121 are tightened, the outer tapered portions 170 of the plug members 167 are compressed between the tapered bore portions and the outer surface of the assembly 152. The outer ends of the bores 151 are countersunk or enlarged as at 178, and compression of the plug members 167 during assembly causes the portions of the plug members 167, adjacent the shoulders 169 to be extruded into the countersinks 178 (FIG. 6). Compression of the plug members 167 also forces the shoulders 169 tightly against upper surface of the end rings 45, `and the remaining portions of the plug members are forced tightly against the walls of the holes 142 and the insulator members 143. Further, the section 154 of each socket assembly 152 is forced tightly against the associated shoulder 167.

After the intermediate unit 23 is secured to the motor module 20, the unit 23 is lowered onto the upper end of the motor module 21 and the prongs 147 are inserted into the bores 164 of the sockets 158. The sleeve coupling 131 is preferably secured to the lower end of the rotor shaft 128 of the motor module 20, and as the motor 20 and the intermediate unit 23 are lowered onto the motor 21, the coupling 131 is slipped over the upper end of the rotor shaft 129 of the motor module 21. Thereafter, as the bolts 121 are tightened to secure the motor module 21 to the intermediate unit 23, the plug members 168` are compressed as previously described to effect seals between the shoulders 171 of the plug members 168 and the outer surface of the end -ring 47', and between the bores of the plug members 168 and the outer surfaces of the socket assemblies 152. The plug members 168 `are also pressed tightly against the walls of the holes 146 and the insulator members 148.

The motor modules 20 and 21 and the intermediate unit 23 may also be assembled by first securing the intermediate unit 23 to the upper end of the module 21 and then securing the unit 23 to the motor module 20.

In the foregoing description, it has been pointed out that the plug members 76, 167 and 168 are replaceable. While this may be advantageous in many instances, in other instances it may be advantageous to have these plug members permanently attached. In such instances, the plug members would be permanently attached as by cementing them to the socket member 67 or the socket assembly 152, as the case may be.

When the module assembly is lowered into a deep well and the assembly is subjected to extremely high ambient liquid pressures, the ambient fluid may enter the interior of the bores 151 between the end of the shells 44 and 44' of the motors and the end surfaces of the anges 118 and 119 of the member 117, and flow into the bores 151 around the outer surfaces of the tapered portions of the plug members 167 and 168. Fliud within the bore 151 would be under very high pressure and would exert a compressive force on the plug members 167 and 168 and increase the effectiveness of the seal as previously explained. If the member 117 is a casting and unless special precautions are taken, the casting may be relatively porous under the extremely high liquid pressures contemplated. Therefore, the ambient liquid may also flow into the bores 151 through the porous casting and compress the plug members as previously explained.

In the event the construction is such that fluid may not readily enter the bores 151, it may be desirable to form small holes through the member 171 extending from the bores 151 to the exterior of the member 117, to permit uid to enter the bores 151 and compress the plug members 167 and 168.

From the foregoing description, it will be apparent that an electrical connector has been provided which includes means for effecting a liquid tight seal even under extremely high tluid pressures. The electrical connectors may be automatically connected together upon assembly of the modules, and the parts of the electrical connector may be easily serviced or replaced when necessary.

We claim:

1. Electrical apparatus for use while submersed in a high pressure liquid, comprising iirst and second units releasably secured together, an electrically conductive prong member secured to one of said units, an electrically conductive socket member secured to the other of said units, said prong and socket members having portions which are in engagement when said units are secured together, a sealing plug member made of a resilient electrical insulating material embracing said portions of said prong and socket members, a cavity formed in one of said units, a portion of said sealing plug member being positioned within said cavity, the unit other than the unit having said cavity including compressing means engaging `a portion of said sealing plug member which is outside of said cavity and compressing said sealing plug member to provide a seal around said portions of said prong and socket members, and said units being constructed such that a portion of said sealing plug member which is outside of said cavity is exposed to said high pressure liquid and thereby increasing the compressive 4`force on said sealing lplug member and thereby increasing the eiectiveness of said seal around said prong and socket members, said portion of said sealing member which is engaged by said compression means being tapered, and said compressing means having a corresponding taper.

2. Electrical apparatus for use while submersed in a high pressure liquid, comprising first and second units releasably secured together, an electrically conductive prong member secured to one of said units, an electrically conductive socket member secured to the other of said units, said prong and socket members having portions which are in engagement when said units are secured together, a sealing plug member made of a resilient electrical insulating material embracing said portions of said prong and socket members, a cavity formed in one of said units, a portion of said sealing plug member being positioned within said cavity, the unit other than the unit having said cavity including compressing means engaging a portion of said sealing plug member which is outside of said cavity and compressing said sealing plug member to provide a seal around said portions of said prong and socket members, and said units being constructed such that a portion of said sealing plug member which is outside of said cavity is exposed to said high pressure liquid and thereby increasing the compressive force on said sealing plug member and thereby increasing the effectiveness of said seal around said prong and socket members, said sealing plug member being generally tubular and the outer surfaces of said sealing plug member at the opposite 'ends thereof being oppositely tapered inwardly toward the respective ends of said sealing plug member, the inner wall of said cavity having a taper which corresponds with the associated portion of said sealing plug member, and said compressing means having a taper which corresponds with the taper of the associated portion of said sealing plug member.

3. Electrical structure =for use while submersed in a high presure fluid, comprising a rst unit, a iirst electrical connector part yfastened to said rst unit, a second unit, a second electrical connector part fastened to said second unit, said first and second units being releasably connected together and said rst and second electrical connector parts having conductor portions mating with each other when said first and second units are connected and being separated when said rst and second units are disconnected, and a sealing plug embracing said portions and providing a seal around said portions against access by the fluid and being compressed by said units and said portions when said units are connected together, at least one end portion of said sealing plug being compressed by said units and said portions and lbeing tapered, and at least one of said units having a taper mating with said compressed tapered end portion of said sealing plug, and being constructed so that said compressed tapered end portion is exposed exteriorly to the high pressure fluid, whereby the pressure of said fluid acting on said tapered end portion of said sealing plug increases the effectiveness of said seal by pressing said plug member tightly against said units and said conductor portions.

References Cited UNITED STATES PATENTS 2,783,298 2/1957 Brown et al. 339-61 X 2,839,595 6/1958 Felts et al 339-100 X 2,892,990 6/ 1959 Werndl. 3,092,431 6/ 1963 vBilbrey. 3,273,107 9/ 1966 Chandler 339-205 3,290,639 12/1966 Driemeyer 339-94 MARVIN A. CHAMPION, Primary Examiner.

J. H. MCGLYNN, Assistant Examiner. 

